Mine roof bolts and the like



Feb. 14, 1967 e. RAYNOVICH, JR 3,303,736

MINE ROOF BOLTS AND THE LIKE Filed April 22, 1964 2 SUPERIMPOSED RIGHT8. LEFT 23 20 HAND THREADS 20 SUPERIMPOSED RIGHT a LEFT H 4 r EIZ T A RF T 42 f3 HAND THREADS 37 38 Vl/A 32 WIIHIIIIIIIIIIIEIIIIII'SUPERIMPOSED Fag 5% A52 Q RIGHT a LEFT 40 4| HAND THREADS 32 1 [111Mhllhl'||l|||||||hhhlllihhllhlllhlllllhlflll 8? 33 34 1\ u \1\ N. 35 3sINVENTOR George Ruynovich Jr.

W Day/5% W? United States Patent 3,303,736 MINE ROOF BOLTS AND THE LIKEGeorge Raynovich, In, Pittsburgh, Pa., assignor to Edward M. Citron,Pittsburgh, Pa. Filed Apr. 22, 1964, Ser. No. 361,859 3 Claims. (CI.85-67) This invention relates to mine roof bolts and like structures andparticularly to mine roof bolts having an expausible locking or holdingmember which may be positioned anywhere on the threaded portion of thebolt and expanded to hold the bolt in the earth.

The use of mine roof bolts for the purpose of supporting a mine roofagainst falling is not new. Many forms of bolts and fasteners have beenproposed. Throughout all of the roof bolt art, however, there hasexisted the problems of anchorage of the bolt and the tightening of thebolt so as to assure pre-st'ressing of the bolt when installed into theroof.

The roof bolt of the present invention solves both of these problems. Itprovides a bolt which will engage firmly within the mine roof and whichcan be tightened to pre-stress the bolt in the roof of the mine.

In a preferred embodiment of my invention I provide an elongated boltmember having an enlarged head on one end and on the opposite end athreaded portion having superimposed right and left hand threads, aright hand threaded nut and a spaced apart left hand threaded nut onsaid threaded portion, a plurality of inclined faces on each of saidnuts, a plurality of wedge shell members having inclined faces matchingthe inclined faces of the nuts and adapted to be forced outwardly bymovement of the nuts with respect to one another longitudinally of thebolt and resilient means acting on the shell members urging into contactwith the inclined surfaces on the nuts. Preferably the nuts have fourinclined faces matching the inclined faces of a like number of Wedgeshells.

In the foregoing general description I have set out certain objects,advantages and purposes of this invention. Other objects, purposes andadvantages will be apparent from a consideration of the followingdescription and the accompanying drawings in which,

FIGURE 1 is an isometric view of a preferred embodiment of my invention;

FIGURE 2 is a longitudinal section with the bolt in elevation of theembodiment of FIGURE 1 in the contracted position;

FIGURE 3 is a longitudinal section with the bolt in elevation of theembodiment of FIGURE 1 in the expanded position;

FIGURE 4 is a longitudinal section with the bolt in elevation of asecond embodiment of my invention in the closed position;

FIGURE 5 is a section of the embodiment of FIGURE 4 in the expandedposition; and

FIGURE 6 is a detailed view showing the superimposed right and left handthreads upon the bolts of FIGURES l-S.

Referring to the drawings I have illustrated a mine roof bolt 10 havingat one end an enlarged supporting shoulder 11 and turning head 12adapted to receive a wrench for turning the bolt. The opposite end ofbolt 10 is provided with right hand threads 13 and superposed left handthreads 14. A right hand threaded nut 15 having inclined faces 16 isthreaded onto the bolt. A left hand threaded nut 17 having a like numberof inclined faces 18 and an elongated cylindrical collar 19 is threadedonto the bolt. A plurality of wedge shell members 20 having a shortinclined surface 21 at one end matching the inclined surfaces 18 on theleft hand nut 17 and a long inclined surface 22 at the opposite endmatching the inclined surfaces 16 on the right hand nut are placed overthe nuts as shown in FIGURE 2. The Wedge shell members 20 are held inposition by a rubber ring 23 or like resilient means such as a spring.The threaded end of the bolt carrying the contracted wedge shells asshown in FIGURE 2 is inserted into a hole drilled in the mine roof inthe usual manner until the collar 11 engages the roof surface. Therubber ring 23 and the Wedge shell members 20 engage the walls of thehole drilled in the mine roof and prevent the nuts from turning as thebolt is turned. The bolt 10 is turned by the head 12, causing the righthand thread nut to move toward the collar 11 and the left hand thread tomove toward the opposite end of the bolt. This causes the inclinedsurfaces 21 and 22 to move up the matching inclined surfaces 18 and 16,respectively of the nuts 15 and 17, expanding the resilient member 23.When the short inclined surfaces 21 reach the top of inclined surfaces18, they rest on cylindrical portion 19 of the nut 17 permitting the nutto turn with the bolt 11 so that its position on the bolt remainsstationary. The longer inclined surfaces 22 continue to bear on inclinedsurfaces 16 on nut 15 and expand the ends of wedge shell members 20nearest the collar 11 to a greater degree than the end with inclines 21providing a wedging and achoring effect and stressing the bolt as thecollar 11 is drawn tightly against the roof surface.

In the embodiment illustrated in FIGURE 4 I provide a roof bolt 30having at one end a collar 31 and a turning head 32 adapted to receive awrench for turning the bolt 30. At the opposite end of the bolt Iprovide right hand threads 33 and superposed left hand threads 34carrying right hand threaded nut 35 and left hand threaded nut 36. Thenut 35 is provided with inclined surfaces 37 and nut 36 with inclinedsurfaces 38. Wedge shell members 39 having inclined faces 40 and 41 atthe opposite ends are placed on the nuts 35 and 36 with the face 40engaging the inclined faces 37 of nut 35 and inclined faces 41 engaginginclined faces 38 of nut 36. A resilient member 42 such as a resilientring holds the wedge shell members 39 in position and urges them towardthe nuts.

The bolt 30 is inserted with the threaded end carrying nuts 35 and 36and shell members 39 in the closed position into a hole drilled in themine roof and the collar 31 bearing against the roof surface. The bolt30 is turned by turning head 32 causing the nuts 35 and 36 to movetoward each other. This causes the inclined surfaces 40 and 41 to moveup faces 37 and 38 of the two nuts 35 and 36 so that the wedge shellsare forced into the sidewalls of the roof hole Wedging the bolt intoposition and stressing it by drawing it tightly into the roof with thecollar 31 bearing on the mine roof surface.

In the foregoing specification I have set out certain preferredembodiments of my invention, however, it will be understood that thisinvention may be otherwise practiced and embodied within the scope ofthe following claims.

I claim:

1. A mine roof bolt comprising an elongated bolt member having anenlarged head portion at one end and a constant diameter threadedportion at the opposite end carrying superimposed right and left handthreads, a right hand thread nut and a spaced apart left hand thread nuteach threaded on said threaded portion, a plurality of inclined faces oneach of said nuts, a plurality of wedge shell members equal in number tothe inclined faces on each nut, said wedge shell members having innerinclined faces matching and bearing on the inclined faces of said nuts,said shell members preventing said nuts from rotating relative to eachother and being adapted to be forced radially outwardly from the axis ofthe bolt by simultaneous longitudinal movement of the nuts relative tothe bolt and resilient means surrounding the wedge shell means urgingsaid shell means toward the inclined faces on the nuts. 3

2. A mine roof bolt comprising an elongated bolt memher having anenlarged head portion at one end and a threaded portion at the oppositeend carrying superimposed right and left hand threads, a right handthread nut and a spaced apart left hand thread nut on said threadedportion, a plurality of inclined planar faces on each of said nuts, thefaces on each of said nuts converging toward the respective ends of thebolt, whereby the larger ends of the nuts are in facing relationship, anintegral cylindrical shell on one of said nuts extending axially thereofaround the bolt from the highest point of said inclined faces toward theother of said nuts, a plurality of wedge shell members equal in numberto the inclined faces on each nut, said wedge shell members having innerinclined faces at each end thereof matching and bearing on the inclinedfaces of said nuts, said shell members being adapted to be forcedradially outwardly from the axis of the bolt by longitudinal movement ofthe nuts on the bolt and resilient means surrounding the wedge shellmeans urging said she-ll means toward the inclined faces on the nuts.

3. A mine roof bolt comprising an elongated bolt member having anenlarged head portion at one end and a threaded portion at the oppositeend carrying superimposed right and left hand threads, a right handthread nut and a spaced apart left hand thread nut on said threadedportion, a plurality of inclined planar faces on each of said nuts, thefaces on each of said nuts converging toward the respective ends of thebolt, whereby the larger ends of the nut are in facing relationship, anintegral cylindrical shell on one of said nut extending axially thereofaround the bolt from the highest :point of said inclined faces towardthe other of said nuts, a plurality of wedge shell members equal innumber to the inclined faces on each nut, said wedge shell membershaving inner inclined faces at each end thereof matching and bearing onthe inclined faces of said nuts, said shell members being adapted to beforced radially outwardly from the axis of the bolt by longitudinalmovement of the nuts on the bolt and resilient means surrounding thewedge shell means urging said shell means toward the inclined faces onthe nuts, the inclined faces of the wedge shell members bearing on theinclined surfaces of the nut carrying the cylindrical shell beingshorter than those on the opposite end of said members whereby saidfaces run off the inclined faces on the nut and bear on the cylindricalshell permitting the nut to turn with the bolt so that its position onthe bolt remains stationary.

References Cited by the Examiner UNITED STATES PATENTS 244,510 7/1881Abernathy 151--16 691,921 1/1902 Wheeler 67 710,534 10/ 1902 Steward85-67 1,349,437 8/1920 Royer 85-67 2,343,283 3/1944 Davis 85-753,009,747 11/1961 Pitzer 8567 FOREIGN PATENTS 213,713 3/1958 Australia.60,919 5/ 1943 Denmark.

CARL w. TOMLIN, Primary Examiner. I

R. S. BRITTS, Assistant Examiner.

3. A MINE ROOF BOLT COMPRISING AN ELONGATED BOLT MEMBER HAVING ANENLARGED HEAD PORTION AT ONE END AND A THREADED PORTION AT THE OPPOSITEEND CARRYING SUPERIMPOSED RIGHT AND LEFT HAND THREADS, A RIGHT HANDTHREAD NUT AND A SPACED APART LEFT HAND THREAD NUT ON SAID THREADEDPORTION, A PLURALITY OF INCLINED PLANAR FACES ON EACH OF SAID NUTS, THEFACES ON EACH OF SAID NUTS CONVERGING TOWARD THE RESPECTIVE ENDS OF THEBOLT, WHEREBY THE LARGER ENDS OF THE NUTS ARE IN FACING RELATIONSHIP, ANINTEGRAL CYLINDRICAL SHELL ON ONE OF SAID NUTS EXTENDING AXIALLY THEREOFAROUND THE BOLT FROM THE HIGHEST POINT OF SAID INCLINED FACES TOWARD THEOTHER OF SAID NUTS A PLURALITY OF WEDGE SHELL MEMBERS EQUAL IN NUMBER TOTHE INCLINED FACES ON EACH NUT, SAID WEDGE SHELL MEMBERS HAVING INNERINCLINED FACES AT EACH END THEREOF MATCHING AND BEARING ON THE INCLINEDFACES OF SAID NUTS, SAID SHELL MEMBERS BEING ADAPTED TO BE FORCEDRADIALLY OUTWARDLY FROM THE AXIS OF THE BOLT BY LONGITUDINAL MOVEMENT OFTHE NUTS ON THE BOLT AND RESILIENT MEANS SURROUNDING THE WEDGE SHELLMEANS URGING SAID SHELL MEANS TOWARD THE INCLINED FACES ON THE NUTS, THEINCLINED FACES OF THE WEDGE SHELL MEMBERS BEARING ON THE INCLINEDSURFACES OF THE NUT CARRYING THE CYLINDRICAL SHELL BEING SHORTER THANTHOSE ON THE OPPOSITE END OF SAID MEMBERS WHEREBY SAID FACES RUN OFF THEINCLINED FACES ON THE NUT AND BEAR ON THE CYLINDRICAL SHELL PERMITTINGTHE NUT TO TURN WITH THE BOLT SO THAT ITS POSITION ON THE BOLT REMAINSSTATIONARY.